Certain 2-(2'3'4'tri-substituted benzoyl)-1,3-cyclohexanedione herbicides are described in U.S. Pat. No. 4,780,127, issued Oct. 25, 1988, U.S. application Ser. No. 129,026, filed Dec. 4, 1987; and a U.S. application entitled 2-(2',3',4'-trisubstituted benzoyl)-1,3-cyclohexanediones, with William J. Michaely, inventor, filed herewith, and all incorporated herein by reference.
The above-described herbicidal compounds can have the following structural formula ##STR1## wherein R.sup.7 through R.sup.12 are hydrogen or C.sub.1 -C.sub.4 alkyl; R.sup.1 is C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, CH.sub.2 CH.sub.2 --OCH.sub.3, CH.sub.2 CH.sub.2 OC.sub.2 H.sub.5, CH.sub.2 CH.sub.2 SCH.sub.3, or CH.sub.2 CH.sub.2 SC.sub.2 H.sub.5 ; R.sup.2 is C.sub.1 -C.sub.4 alkyl; and n is the integer 0 or 2.
These herbicides can be prepared by reacting a dione of the structural formula ##STR2## wherein R.sup.7 through R.sup.12 are as defined with a mole of trisubstituted benzoyl chloride of the structural formula ##STR3## wherein n, R.sup.1 and R.sup.2 are as defined above.